There are quite a few motels right near the boarder of GA/FLA. All are well advertized. When you get into FLA, stop in Ocala at the WDW Welcome center. They can give you maps of the property and show you the easiest way to get in. When I have driven down from Atlanta, I don't go all the way to I4, I take the FL tpk and then get off on exit that take you thorough a little back road short cut. You go by the Orange Tower, that much I do know. Just ask at the welcome center, they will highlight it for you.
BTW, the speed limit drops in FL, and there are plenty of unmarked cars patroling.
Have fun at the Movies, it is a great resort. Been there twice and loved it both times.